The number of children under 10 who own mobile phones doubled in the last two years, despite warnings over potential health risks, a survey has found.
Health experts say children under eight should not use mobiles
An analysis by international research consultancy MobileYouth showed just over a million children aged five to nine in the UK have their own phones.
The figure is predicted to rise to 1.5 million by 2007.
Radiation experts say there is no proven health risk, but say parents should take a "precautionary approach".
Experts said there was a contradiction between parents being happy for their children to have mobile handsets and not wanting mobile phone masts, which emit lower levels of radiation, to be erected near schools.
MobileYouth, which gathered data from retailers, parents and children,industry bodies and mobile phone companies, predicted the number of under-16s in the UK owning a mobile phone will grow to 5.5 million this year, up by almost half a million compared to last year.
The average age at which a child gets a first phone in the UK is eight - compared to 12 in the US.
'No proven health risk'
Advice issued in January this year by Sir William Stewart, in his second report on mobile phone safety, said children under eight should not use mobile phones at all.
He suggested that, if there were risks from the radiation emitted by mobile phones, children would be at a higher risk that adults.
Following his report, the UK's first mobile phone specially designed for children was withdrawn from sale by distributor Communic8 earlier this year after a government report raised health concerns about youngsters using handsets.
The MyMo phone was aimed at four to eight-year-olds to use in an emergency.
Michael Clarke, radiation expert at the Health Protection Agency, said: " "We feel we should discourage prolonged use of mobile phones.
"There isn't actually a proven health risk. What we are talking about is the possibility of one emerging after prolonged use.
He added: "Our view is that it is sensible to take a precautionary approach to mobile use, especially in the very young, because it is such a new thing. I cannot predict what I might find out tomorrow.
"Children should not be spending hours a day talking to their friends.
"Parents are the best people to judge the needs of their children but they should have all the information."